org.apache.commons.collections4.functors
Class SwitchTransformer<I,O>

java.lang.Object
  extended by org.apache.commons.collections4.functors.SwitchTransformer<I,O>
All Implemented Interfaces:
Serializable, Transformer<I,O>

public class SwitchTransformer<I,O>
extends Object
implements Transformer<I,O>, Serializable

Transformer implementation calls the transformer whose predicate returns true, like a switch statement.

Since:
3.0
Version:
$Id: SwitchTransformer.java 1479337 2013-05-05 15:20:59Z tn $
See Also:
Serialized Form

Constructor Summary
SwitchTransformer(Predicate<? super I>[] predicates, Transformer<? super I,? extends O>[] transformers, Transformer<? super I,? extends O> defaultTransformer)
          Constructor that performs no validation.
 
Method Summary
 Transformer<? super I,? extends O> getDefaultTransformer()
          Gets the default transformer.
 Predicate<? super I>[] getPredicates()
          Gets the predicates.
 Transformer<? super I,? extends O>[] getTransformers()
          Gets the transformers.
static
<I,O> Transformer<I,O>
switchTransformer(Map<? extends Predicate<? super I>,? extends Transformer<? super I,? extends O>> map)
          Create a new Transformer that calls one of the transformers depending on the predicates.
static
<I,O> Transformer<I,O>
switchTransformer(Predicate<? super I>[] predicates, Transformer<? super I,? extends O>[] transformers, Transformer<? super I,? extends O> defaultTransformer)
          Factory method that performs validation and copies the parameter arrays.
 O transform(I input)
          Transforms the input to result by calling the transformer whose matching predicate returns true.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

SwitchTransformer

public SwitchTransformer(Predicate<? super I>[] predicates,
                         Transformer<? super I,? extends O>[] transformers,
                         Transformer<? super I,? extends O> defaultTransformer)
Constructor that performs no validation. Use switchTransformer if you want that.

Parameters:
predicates - array of predicates, cloned, no nulls
transformers - matching array of transformers, cloned, no nulls
defaultTransformer - the transformer to use if no match, null means return null
Method Detail

switchTransformer

public static <I,O> Transformer<I,O> switchTransformer(Predicate<? super I>[] predicates,
                                                       Transformer<? super I,? extends O>[] transformers,
                                                       Transformer<? super I,? extends O> defaultTransformer)
Factory method that performs validation and copies the parameter arrays.

Type Parameters:
I - the input type
O - the output type
Parameters:
predicates - array of predicates, cloned, no nulls
transformers - matching array of transformers, cloned, no nulls
defaultTransformer - the transformer to use if no match, null means return null
Returns:
the chained transformer
Throws:
IllegalArgumentException - if array is null
IllegalArgumentException - if any element in the array is null

switchTransformer

public static <I,O> Transformer<I,O> switchTransformer(Map<? extends Predicate<? super I>,? extends Transformer<? super I,? extends O>> map)
Create a new Transformer that calls one of the transformers depending on the predicates.

The Map consists of Predicate keys and Transformer values. A transformer is called if its matching predicate returns true. Each predicate is evaluated until one returns true. If no predicates evaluate to true, the default transformer is called. The default transformer is set in the map with a null key. The ordering is that of the iterator() method on the entryset collection of the map.

Type Parameters:
I - the input type
O - the output type
Parameters:
map - a map of predicates to transformers
Returns:
the switch transformer
Throws:
IllegalArgumentException - if the map is null
IllegalArgumentException - if any transformer in the map is null
ClassCastException - if the map elements are of the wrong type

transform

public O transform(I input)
Transforms the input to result by calling the transformer whose matching predicate returns true.

Specified by:
transform in interface Transformer<I,O>
Parameters:
input - the input object to transform
Returns:
the transformed result

getPredicates

public Predicate<? super I>[] getPredicates()
Gets the predicates.

Returns:
a copy of the predicates
Since:
3.1

getTransformers

public Transformer<? super I,? extends O>[] getTransformers()
Gets the transformers.

Returns:
a copy of the transformers
Since:
3.1

getDefaultTransformer

public Transformer<? super I,? extends O> getDefaultTransformer()
Gets the default transformer.

Returns:
the default transformer
Since:
3.1


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